Abnormalities in event-related potentials: N100, N200 and P300 topography in alcoholics.

Event-related potentials were recorded in 30 abstinent alcoholics, and 30 gender- and age-matched controls during a two-tone discrimination (odd ball) task. All the subjects were free from medication and dextral. The amplitudes of N100, N200 and P300 in the alcoholics were reduced and the P300 latency prolonged as compared with those of the controls. A P300 amplitude reduction occurred in the left and midline frontal, and the left and midline central regions. This is the first report of the amplitude of P300 being markedly decreased in the left hemispheres of the brains of the alcoholics. The results are discussed in terms of the cognitive dysfunctions of alcoholics.